Differential pressure transducer process mounting support

ABSTRACT

A mounting support serving as an interfacing connection between a process vessel or a valve or other fluid pressure transmitting structure connected to a process vessel and an instrument capable of sensing the differential pressure between the vapor-space pressure and the hydrostatic head pressure of fluid within the process vessel for the purpose of meansuring liquid level within the vessel. The mounting support in addition to providing structural support for the differential pressure sensing apparatus serves to transmit vapor pressure to the low side and hydrostatic head pressure to the high side of the differential pressure mechanism. The support may also be provided with a bypass passage between high and low pressure passages within the support for the purpose of establishing a balanced pressure condition between the low pressure and high pressure sides of the differential pressure sensing mechanism for the purpose of calibration, which bypass passage is provided with appropriate valve means to control fluid communication between the passages. The support includes orienting means to insure proper installation thereof.

United States Patent [191 Hewson [76] Inventor: John E. Hewson, 12211 Broken Arrow, Houston, Tex. 77024 [22] Filed: May 30, 1972 [21] Appl. No.: 258,019

1 Related US. Application Data [63] Continuation-impart of Ser. No. 132,165, April 7,

1971, abandoned.

521 Us. Cl. 137/608 [51] Int. Cl. Fl7d l/00 [58] Field of Search..... 137/608, 270, 271

[56] References Cited UNITED STATES PATENTS 2,940,798 6/1960 Weber 137/270 X 2,966,168 12/1960 Hunt et a1 137/270 3,357,444 12/1967 Zeuner 137/270 3,384,114 5/1968 Hathaway et a1. 1 137/608 3,473,568 10/1969 Pfitzner et a1. 137/608 3,561,469 2/1971 Kellstrom et a1. 137/608 3,596,680 3/1971 Adams... 3,599,669 8/1971 3,654,960 4/1972 3,680,589 8/1972 1 June 18, 1974 Primary Examiner-Samuel Scott Attorney, Agent, or Firm-James L. Jackson [57] ABSTRACT A mounting support serving as an interfacing connection between a process vessel or a valve or other fluid pressure transmitting structure connected to a process vessel and an instrument capable of sensing the differential pressure between the vapor-space pressure and the hydrostatic head pressure of fluid within the process vessel for the purpose of meansuring liquid level within the vessel. The mounting support in addition to providing structural support for the differential pressure sensing apparatus serves to transmit vapor pressure to the low side and hydrostatic head pressure to the high side of the differential pressure mechanism. The support may also be provided with a bypass passage between high and low pressure passages within the support for the purpose of establishing a balanced pressure condition between the low pressure and high pressure sides of the differential pressure sensing mechanism for the purpose of calibration, which bypass passage is provided with appropriate valve means to control fluid communication between the passages. The support includes orienting means to insure proper installation thereof.

17 Claims, 10 Drawing Figures PATENTED-Juu 181974 sum 1 or 4 6 am m Hi7 John E. Hewson IN VENTOR WM A TTORNEY PATENTEBJummu 3.817.283

FIGS

FIG. 7

FIG. 6

DIFFERENTIAL PRESSURE TRANSDUCER PROCESS MOUNTING SUPPORT This is a continuation-in-part of application Ser. No. 132,165 filed Apr. 7, 1971, and now abandoned.

BACKGROUND OF THE INVENTION The invention relates generally to differential pressure sensing devices and more particularly to a mounting and fluid pressure transfer support for supporting and transmitting fluid pressure to a differential pressure sensing mechanism.

In the process industries (refineries, chemical plants, gasoline plants, and the like) it is common that the level of liquids within process vessels be measured and visually displayed as an available guide to the operating personnel of the condition of the process at all times. Although there are many ways in which the level of liquid within a process vessel may be measured one of the more economical methods for remote sensing and transmission of the liquid level in the form of appropriate signals to an operating facility lies in the use of devices that measure the hydraulic or hydrostatic head produced by the height of liquid on the measuring device. Such fluid level measuring devices are commonly referred to as differential pressure transmitters. Virtually all processes are maintained under either positive static pressure or vacuum and therefore it is necessary to sense the process pressure both above and below the liquid level. For example, if a process were maintained within a vessel at a gauge pressure of 500 psi and the vessel were partially filled with liquid, the level of which is to be sensed, it is necessary for the low pressure side of a differential pressure sensing mechanism to sense the vapor pressure or 500 psi. The high pressure side of the differential pressure sensing mechanism however will sense not only the vapor pressure of 500 psi, but also the pressure of the hydrostatichead of the liquid within the vessel. It is obvious, therefore, when using this type of measuring device, that the differential between the high pressure and low. pressure sides of the differential pressure sensing mechanism will amount to only the hydrostatic head of the liquid within the vessel. The instrument, therefore, will transmit a signal proportional only to the liquid level for which the instrument is calibrated.

Differential pressure sensing mechanism, commonly referred to as d/p cells, are generally mounted adjacent to the process vessel with which it is associated by providing a length of pipe frequently of 2 inch diameter that is securely cemented or otherwise fixed in position in order to provide a vibration free support structure.

The d/p cell is then mounted on the 2 inch pipe structure with tubing or small bore pipe connecting the sensing element to the process vessel. The two inch pipe stand may be welded to a nearby structural member or to the vessel itself or may be mounted in a block of concrete especially provided for the purpose of installation of the d/p cell.

Such methods of mounting the d/p cells are disadvantageous because of the expensive nature of providing a vibration free support. Another disadvantage is the involvement between trade unions such as pipefitters and instrument technicians due to the overlappingsubject matter of pipe structure for support andttubing structure for instrumentation. Moreover, the various possible methods of installation adversely affect any tendency toward standardization of mounting practice at the engineering stage of development.

It is a primary object of this invention, therefore, to provide a novel mounting support serving as an interfacing connection between a process vessel and a dif ferential pressure sensing instrument in addition to providing structural support for the instrument.

It is another object of this invention to provide a novel mounting support construction that simply and positively establishes structural support for differential pressure sensing apparatus and further serves to trans mit fluid pressures from a process vessel to the pressure sensing mechanism.

Among the several objects of this invention is contemplated the provision of a novel mounting support structure whichprovides process connections to both the high andlow signal sides of a differential pressure sensing instrument and providesfor complete removal of theinstrument for repair without disturbing the process piping in any manner.

It is another important object of this invention to provide a novel mounting support structure including orienting means to prevent improper installation of the differential pressure sensing mechanism.

The above and other objects and novel features of the instant invention will be readily apparent from the following description taken in conjunction with the accompanying drawings. It is to be expressly understood that the drawings are for the purpose of illustration and are not intended to define the limits of the invention but rather to merely illustrate preferred embodiments and structures incorporating the features of the instant invention.

In the accompanying drawings forming a part of this specification and wherein like reference numerals are employed to designate like parts:

FIG. 1 is an isometric illustrationof the mounting support comprising the preferred embodiment of this invention.

FIG. 2 is a plan view of the mounting support structure of FIG. I in section illustrating connection of the mounting support to a process vessel and a differential pressure sensing mechanism.

FIG. 3 is an elevational view in section of a modified embodiment being connected at one extremity to the flanged outlet of a valve structure and connected at the other extremity to a differential pressure sensing mechanism.

FIG. 4 is an elevational view of a further modified embodiment of my invention illustrating the interfacing surfacesin detail.

FIG. 5 is a plan view in section of a further modified embodiment of my invention.

FIG. 6 is a side .view of amounting support, representing a modified embodiment of the present invention.

FIG. 7 is a sectional view of the mounting support of FIG. 6, illustrating the high and low pressure passages thereof and illustrating a purge passage being communicated with the high pressure passage.

FIG. 8 is an end view of the mounting support of FIG. 6, illustrating the connection flange of the support in detail.

FIG. 9 is asectional view of a modified embodiment of the present invention illustrating incorporation of an inlet valve structure to control the transmission of process pressure through the mounting support.

FIG. is a sectional view of a further modified embodiment of the present invention further adding to the structure of FIG. 9, a pressure balancing passage and a valve structure provided for controlling the communication of process pressure from the high pressure passage of the mounting support to the low pressure passage thereof for the purpose of balancing pressure in both chambers of the differential pressure sensing apparatus secured to the mounting support.

Briefly the invention concerns the provision of a mounting support structure which is connected at one extremity thereof to the lower region of a process vessel or to a valved outlet or outlet conduit at the lower region of the process vessel and provides the sole support for a differential pressure sensing mechanism. The mounting support includes fluid passage structure conducting combined process pressure and hydrostatic pressure directly to the high pressure side of a differential pressure sensing mechanism and conducting process pressure only to the low pressure side of the differential pressure sensing mechanism. The mounting support also includes pressure transmission passage structure which is connected by means of piping to the upper extremity of a process pressure and to transmit this pressure to the low pressure or process pressure side of the d/p cell. The mounting support structure therefore serves as the sole physical support for the differential pressure sensing mechanism and also transmits both pressures to be sensed to the pressure sensing apparatus. The mounting support structure may also be provided with valve devices capable of isolating one or both of the fluid pressures from the pressure differential sensing mechanism and may also include a valve controlled bypass passage capable of allowing simple zeroing of the pressure sensing apparatus.

With reference now to the drawings for a more thorough understanding of my invention, in FIG. 1 is illustrated a mounting support structure generally at 10 comprising a support body 12 having a threaded connection portion 14 for securing the adaptor body within a threaded aperture 16 formed in the wall structure of a process vessel 18 as illustrated in FIG. 2 or formed in structure fixed to the wall of the vessel. The mounting support 12 may also include an integral flange structure as shown in broken line at 20 in FIG. 1 for connection of the support body structure to the flanged outlet of a valve or conduit through which fluid pressure is supplied to the support body structure. If desired, the support body may be provided with a generally cylindrical connection portion at 14 which may be fitted into an aperture in a process vessel and welded into assembly with the vessel. An integral connection flange 22 is provided at the other extremity of the support body 12 and is provided with a plurality of bolt holes 24 through which bolts extend to secure a differential pressure sensing mechanism illustrated generally at 26 in FIG. 2 to the integral flange 22 of the support body.

As illustrated particularly in FIG. 2 the support body 12 is provided with a substantially straight passage 28 disposed in angular relationship with respect to the horizontal axis of the support body and terminating at the planar surfaces 30 and 32 defined at each extremity of the support body. A second fluid passage 34 is formed within the flange portion 22 of the support body 12 and terminates at one extremity at the substantially planar surface 32. A threaded aperture terminating at the outer surface of the connection flange 22 defines a portion of the fluid passage 34. A conduit 38 is connected at one extremity to the internal threads 36 of the passage 34 and the other extremity to a threaded aperture 40 formed in the wall structure of the process vessel 18 at the upper vapor region thereof.

For the purpose of establishing fluid seals between the mounting support and the differential pressure sensing mechanism, the mounting support is provided with annular recesses 42 and 44 formed about the fluid passages 28 and 34 respectively each receiving O-ring type sealing mebers 46 and 48. When the differential pressure sensing mechanism 26 is drawn into abutting engagement with the planar surface 32 of the flange portion 22, the O-ring members 46 and 48 will be compressed against sealing surfaces 50 and 52 respectively formed on the differential pressure sensing mechanism.

As illustrated generally in FIG. 2, the differential pressure sensing mechanism 26 includes a large body section 54 and a smaller body section 56 which are secured together by bolts or the like. The body section 54 ordinarily includes most of the moving parts of the differential pressure sensing mechanism and cooperates with the body section 56 to define a nonsymmetrical body configuration. Most d/p cells of this nature are manufactured with a nonsymmetrical body configuration such as shown in the drawings, but the invention is not intended to be limited to d/p cells having nonsymmetrical body configuration. For the purpose of establishing positive orientation between the d/p cell and the support body, an orienting member 58 is formed integrally with the support body. The integral flange or elongated projection 58 is received within a depression defined by the joined body sections 54 and 56 when fluid passages 62 and 64 in the d/p cell are disposed in fluid registry with the fluid passages 28 and 34 of the support body 12 respectively. In the event the d/p cell were so oriented that the passage 62 is disposed in registry with the fluid passage 34, it should be obvious that the elongated projection 58 will not properly register with the depression and therefore the d/p cell cannot be installed in this manner. Most d/p cells are so designed that fluid pressure conduit structure may be connected at either extremity thereof as illustrated particularly in FIG. 2. Ordinarily the unused extremity receives a plug to close the unused connection opening. It is apparent as shown in FIG. 2 that the d/p cell may be reversed placing the other extremity thereof in fluid communication with the passages 28 and 34 of the mounting support. Again proper connection of the d/p cell to the mounting support can only be accomplished by registering the high pressure fluid input passage 66 thereof with the high pressure fluid transfer passage 28 and by disposing the low pressure fluid passage 68 in fluid communication with the passage 34 of the mounting support. The orienting projection 58 again will be received within the depression 60 defined by the joined body sections 54 and 56, and improper assembly of the d/p cell to the mounting support will not be possible. In the event a d/p cell should include a symmetrical body configuration, proper orientation may be achieved by providing off-center pinsand mating pin apertures which register only when the d/p cell is properly oriented with respect to the mounting support.

With reference now to FIG. 3 a modified embodiment of my invention may comprise a mounting support illustrated generally at 70 and being connected to high pressure fluid supply structure in similar manner as discussed above with regard to the mounting adaptor 10. Likewise the mounting support 70 is connected to a differential pressure sensing mechanism in essentially the same manner and for the same purpose as setforth above. The mounting support 70 includes a high pressure fluid supply passage 72 extending through the adaptor body in the same manner as the passage 28 as illustrated in FIG. 2. The passage 72 is provided with a valve element 74 capable of isolating the high pressure'fluid supply passage 72 from the fluid pressure being transmitted from the lower region of the process vessel. The valve element 74 may be any one of a number of acceptable valve types including spherical plug valves, needle valves, and the like. The valve element 74 when closed will serve to isolate the high pressure side of the differential pressure sensing mechanism from the fluid pressure transmitted from the lower region of the process vessel.

The modified mounting support of FIG. 3 also includes a bypass passage 76 communicating between the high pressure fluid passage 72 and a low pressure or process pressure fluid passage 78. Communication be tween the high pressure fluid passage 72 and the low pressure passage 78 through the bypass passage 76 is controlled by a valve element 80 provided within the support body 70. The valve element 80 may also be any one of a number of commercially acceptable valve types within the spirit and scope of this application. The bypass passage 76 is employed for the purpose of establishing proper adjustment of the differential pres sure sensing mechanism. This feature is generally known as zeroing the pressure sensing apparatus. To accomplish zeroing the valve element 74 may be closed in order to isolate the high fluid pressure at the lower region of the process vessel from the passage 72. The bypass valve 80 is opened to communicate low pressure conducted from the upper or vapor region of the process vessel through conduit structure 82 to the high pressure passage 72. The process pressure is transmit ted through the bypass passage to the high pressure passage 72 thereby establishing a balanced pressure condition within both of the passages 72 and 78. The pressure sensing instrument may then be set at zero in dicating that no pressure differential exists between the high pressure and low pressure sides of the instrument. It is obvious that zeroing of the instrument may also be accomplished by closing a valve 84in the process pressure conduit 82 and by opening the high pressure valve 74 and the bypass valve 80. When this is done the combined process and hydrostatic pressure at the lower region of the process vessel is communicated to both the high pressure and low pressure passages 72 and 78 respectively. Fluid pressure transmitted from both the high pressure and low pressure input passages will be balanced thereby establishing a balanced pressure condition between the high pressure and low pressure sides of the pressure sensing instrument. It is oftentimes essential that zeroing be performed with full process pressure on the d/p instrument to eliminate any errors in measurement due to pressure strain in the body of the instrument.

With reference now to FIG. 4 a further modified embodiment of my invention comprises a adaptor body illustrated generally at 86 including a valve element 88 for the high pressure fluid passage 90 thereof and a valve 92 controlling the flow of fluid through a low pressurefluid passage 94 formed within the support a differential body 86. This feature allows selective isolation of either the high pressure or low pressure sides of the differential pressure sensing instrument from either the high pressure or vapor pressure supplied to the instrument through the support body. Checking or repair of the pressure sensing apparatus may be achieved without the necessity for shuting down the process and without the necessity for gaining access to the top of the process vessel in order to close a process valve.

With reference now to FIG. 5 the connection flange 22 of the support body 12 may be provided with a plurality of input passages 96 and 98 each communicating with the low pressure input passage 34 of the support body. These passages are so arranged to allow various orientations of the support body relative to the process vessel. The low pressure input conduit 38 is shown as being connected to the passage 34 and the other passages are shown as being closed by plug members 100 g and 102. It is obvious that the low pressure input conduit may be connected to any of the other openings to the passages 96 and 98 and the plug members 100 and 102 may be employed to close the unused openings.

With reference now to FIG. 6 a modified embodiment of the present invention may incorporate an integral support body illustrated generally at .104 that may be formed by any conventional method such as forging, casting, machining or the like. The support 104 may include an integral body 106 having a threaded connection element 108 or any other suitable connection structure formed at one extremity thereof and may have a flanged connection structure 110 defined at the opposite extremity of the integral body. As shown in FIG. 8 the flanged connection 110 may incorporate a pair of spaced flanges 112 and 114 each being provided with bolt apetures 116 and 118 respectively for connection of differential pressure sensing apparatus, commonly referred to as a d/p cell, to the support.

As illustrated in- FIG. 7 the support 104 may be provided with a high pressure inlet passage 120 terminating at an inlet aperture 122 at one extremity of the support and terminating at an aperture: 124 at the opposite extremity thereof which defines an outlet aperture of the support and inlet aperture for a DIP cell that may be connected to the support. The passage 120 may be .conveniently referred to as the high pressure passage.

may extend completely through the body 106 and may 7 receive a threaded purge conduit such as shown in broken line at 111, or, if desired, may simply be closed by a plug shown in broken line at 113.

A purge passage 107 may also be formed in the body 106 in intersecting relation with the high pressure passage 124 and may receive a threaded purge conduit 109 for the purpose of purging the mounting support of any process fluid that might be of corrosive nature. The purge conduit may be connected to any suitable source of purging fluid.

For the purpose of controlling flow of pressurized fluid from the vessel through the supported aperture and the D/P cell it may be desirable to provide the support with one or more valves for controlling the same. As shown in FIG. 9 a support 132 representing a modified embodiment of the present invention may be provided with an inlet or high pressure flow passage 134 having a valve seat 136 defined therein. A valve mechanism 138 which may conveniently take the form of a conventional needle valve, a ball valve or any other suitable valve mechanism may be carried by the support and may include valve element 140 that may be conveniently manipulated to cause opening and closing of the inlet passage 134. In the embodiment shown in FIG. 9 a low pressure passage 142 may be formed substantially identically with respect to the low pressure passage 126 illustrated in FIG. 7. A purge passage 138 may be'formed in the support 132 and may intersect the high pressure passage 134 for the purpose of purging the high pressure side of the support.

A support 144 representing a further modified embodiment of the present invention may be constructed as illustrated in FIG. and may include a high pressure or inlet passage 146 including a valve mechanism 148 constructed substantially identically with respect to the inlet passage and valve mechanism 134 and 138 illustrated in FIG. 9. A low pressure passage 150 may also be formed in the support 144 and may be constructed substantially identically with respect to the low pressure passage 142 illustrated in FIG. 9. A bypass passage 152 having a bypass valve seat 154 defined therein may be disposed in interconnecting relation with the low pressure passage 146 and high pressure passage 150. A valve mechanism 156 having a valve element 158 carried thereby may be manufactured into the support 144 and may be manipulated manually to control opening and closing of the bypass passage 152. The bypass passage 152 is similar to the bypass passage 176 illustrated in FIG. 3 and is utilized for the purpose of balancing pressure on both the high pressure and low pressure sides of a d/p cell for the purpose of calibration. Additionally, a purge passage 149 may be formed in the adaptor 144 in communication with high pressure passage 146.

It is apparent in view of the foregoing that I have provided a novel mounting support structure for establishing an interfacing connection between a process vessel and a differential pressure sensing apparatus establishing positive vibration free structural support for the differential pressure sensing apparatus and serving to transmit both high pressures and low pressures from a process vessel to the pressure sensing mechanism. My invention includes novel mounting support structure including means for orienting the differential pressure sensing mechanism to the mounting support in order to prevent improper assembly of the instrument to the mounting adaptor. The mounting support structure may also include valve structure for isolating either or both of the high pressure and low pressure sides of the instrument from the fluid pressure of the process vessel in order to allow simple unbolting and removal of the instrument for testing or repair without necessitating shuting down of the process. The support body structure of ,my invention may also include a valved controlled bypass allowing the establishment of balanced pressure across both the high pressure and low pressure sides of the differential pressure sensing instrument for the purpose of allowing zeroing of the instrument. It is readily understood therefore that my invention is well adapted to attain all of the objects and advantages hereinabove set forth together with other advantages which are inherent in the apparatus itself.

I claim:

1. A mounting support for supporting differential pressure sensing apparatus from the wall structure of a process vessel, said apparatus comprising a support body, first connection means defined at one extremity of said support body for establishing supporting connection of said support body to said vessel, second connection means defined at the opposite extremity of said support body, differential pressure sensing apparatus being secured to said second connection means. first pressure transmitting passage means extending through said body and terminating at each of said connection means, and communicating said differential pressure sensing apparatus with said process vessel, second fluid passage means extending through said support body and having one extremity terminating at said second connection means and having its other extremity terminating at the exterior of said support body.

2. A mounting support as recited in claim 1, an orienting member extending from said mounting support and cooperating with said differential pressure sensing apparatus in order to prevent improper assembly of said differential pressure sensing apparatus to said mounting support.

3. A mounting support as set forth in claim 1, said second fluid passage means comprising a plurality of interconnected pressure inlet passages each terminating at inlet connection apertures on different sides of said support body, whereby said mounting support may be oriented in any desired manner and connection may be made between a low pressure supply conduit and a selected one of said inlet passages and the remaining ones of said inlet passages may be plugged.

4. A mounting support as recited in claim 1, a pressure balancing passage formed in said support body and interconnecting said first and second passage means, said support body having a controllable valve for controlling pressure communication through said pressure balancing passage.

5. A mounting support as recited in claim 4, said support body having a controllable pressure inlet valve disposed in said first passage and being located ahead of of said controllable valve.

6. A mounting support for differential pressure sensing apparatus having high pressure and low pressure fluid pressure inlet means, said support comprising a support body, first integral connection means at one extremity of said support body for supporting connection of said support body to the lower wall structure of a process vessel, second integral connection means at the other extremity of said support body for establishing connection between said mounting support and said differential pressure sensing apparatus and defining a connection surface whereby said differential pressure sensing apparatus will-be solely supported in connection with said pressure transmitting apparatus by said mounting support, a high range pressure transmitting passage extending through said support body and terminating at said connection surface and at said first connection means, a low range pressure transmitting passage extending through said support body and terminating at said connection surface and at the exterior of said support body, means establishing a fluid seal between said connecting surface and said pressure sensing apparatus about each of said passages.

7. A mounting support as set forth in claim 6, orienting means cooperating with structure onsaid differential pressure sensing apparatus to properly orient said differential pressure sensing apparatus relative to said mounting support.

8. A mounting support as set forth in claim 7, said orienting means comprising an elongated rib extending in non-centered relation from said mounting support beyond said connection surface, said elongated rib being received within off-center depression means defined by said differential pressure sensing apparatus only in the properly oriented relation thereof.

9. A mounting support as set forth in claim 6, a pressure balancing passage formed in said mounting support and establishing fluid communication between said high range and low range pressure transmitting passages, said mounting support having a controllable balancing valve means controlling pressure communication between said high pressure and low pressure fluid passages.

10. A mounting support as set forth in claim 9, said mounting adaptor having a pressure inlet valve disposed in said high range pressure passage upstream of said balancing valve for isolation of said passages from said high pressure.

11. A mounting support for supporting differential pressure sensing apparatus from the wall structure of a process vessel, said support comprising a support body, connection means and connection flange means formed integrally with said support body at opposite.

extremities thereof, said connection means being adapted for connection to the wall structure of said process vessel, said connection flange means being adapted for connection to said differential pressure sensing apparatus whereby said support body completely supports said sensing apparatus from said process vessel, said connection flange means defining a connection surface, a high range pressure transmitting passage extending through said support body and terminating at one extremity at said connection means and terminating at the other extremity at said connection surface in off-center relation, low range pressure transmitting passage means extending through said body and terminating at one extremity thereof at said connection surface and terminating at the other extremity thereof at connection aperture means located at the exterior of said support body, means establishing pressure seals between said differential pressure sensing apparatus and about said low and high range pressure transmitting passages.

12. A mounting support as set forth in claim 11, orienting means extending from said mounting support and cooperating with structure on said differential pressure sensing apparatus to prevent improper assembly of said differential pressure sensing apparatus to said mounting support.

13. A mounting support as recited in claim 11, said low pressure passage means comprising a plurality of interconnected passages each terminating at connection apertures on different sides of said support body, whereby said mounting support may be oriented in any desired manner and connection may be made between a low pressure supply conduit and a selected one of the interconnected passages and the remaining ones of the interconnected passages may be plugged.

14. In combination; a vessel having a wall structure, a high pressure aperture formed in the lower portion of said wall structure and a low pressure aperture being defined in the upper portion of said vessel, connection means being defined in said wall structure about said high pressure aperture, a mounting support, first and second connection means being defined on said support, said first connection means being received by said connection means of said vessel and securing said support in assembly with said vessel, differential pressure sensing apparatus being secured to said second connection means and being solely supported by said mounting support, said differential pressure sensing apparatus having a high pressure chamber and a low pressure chamber, first pressure transmittinG passage means being defined in said mounting support and communicating said high pressure aperture with said high pressure chamber, second pressure transmitting passage means being defined in said mounting support and having one extremity thereof disposed in communication with said low pressure chamber and the other extremity thereof terminating at a low pressure connection aperture defined exteriorly of said support, means commu nicating said low pressure connection aperture of said support, with said low pressure connection aperture of said vessel.

15. The combination of claim 14, a purge passage being defined in said mounting support and intersecting said first pressure passage means, means communicating said purge passage with a source of purging fluid.

16. The combination of claim 14, a pressure balancing passage being formed in said mounting support and communicating said first and second pressure passage means, valve means carried by said mounting support and controlling pressure communication between said first and second passage means.

17. The combination Of claim 1.6, inlet valve means being carried by said mounting support and controlling communication of pressure from said high pressure aperture of said vessel to said differential pressure sensing apparatus. 

1. A mounting support for supporting differential pressure sensing apparatus from the wall structure of a process vessel, said apparatus comprising a support body, first connection means defined at one extremity of said support body for establishing supporting connection of said support body to said vessel, second connection means defined at the opposite extremity of said support body, differential pressure sensing apparatus being secured to said second connection means, first pressure transmitting passage means extending through said body and terminating at each of said connection means, and communicating said differential pressure sensing apparatus with said process vessel, second fluid passage means extending through said support body and having one extremity terminating at said second connection means and having its other extremity terminating at the exterior of said support body.
 2. A mounting support as recited in claim 1, an orienting member extending from said mounting support and cooperating with said differential pressure sensing apparatus in order to prevent improper assembly of said differential pressure sensing apparatus to said mounting support.
 3. A mounting support as set forth in claim 1, said second fluid passage means comprising a plurality of interconnected pressure inlet passages each terminating at inlet connection apertures on different sides of said support body, whereby said mounting support may be oriented in any desired manner and connection may be made between a low pressure supply conduit and a selected one of saiD inlet passages and the remaining ones of said inlet passages may be plugged.
 4. A mounting support as recited in claim 1, a pressure balancing passage formed in said support body and interconnecting said first and second passage means, said support body having a controllable valve for controlling pressure communication through said pressure balancing passage.
 5. A mounting support as recited in claim 4, said support body having a controllable pressure inlet valve disposed in said first passage and being located ahead of of said controllable valve.
 6. A mounting support for differential pressure sensing apparatus having high pressure and low pressure fluid pressure inlet means, said support comprising a support body, first integral connection means at one extremity of said support body for supporting connection of said support body to the lower wall structure of a process vessel, second integral connection means at the other extremity of said support body for establishing connection between said mounting support and said differential pressure sensing apparatus and defining a connection surface whereby said differential pressure sensing apparatus will be solely supported in connection with said pressure transmitting apparatus by said mounting support, a high range pressure transmitting passage extending through said support body and terminating at said connection surface and at said first connection means, a low range pressure transmitting passage extending through said support body and terminating at said connection surface and at the exterior of said support body, means establishing a fluid seal between said connecting surface and said pressure sensing apparatus about each of said passages.
 7. A mounting support as set forth in claim 6, orienting means cooperating with structure on said differential pressure sensing apparatus to properly orient said differential pressure sensing apparatus relative to said mounting support.
 8. A mounting support as set forth in claim 7, said orienting means comprising an elongated rib extending in non-centered relation from said mounting support beyond said connection surface, said elongated rib being received within off-center depression means defined by said differential pressure sensing apparatus only in the properly oriented relation thereof.
 9. A mounting support as set forth in claim 6, a pressure balancing passage formed in said mounting support and establishing fluid communication between said high range and low range pressure transmitting passages, said mounting support having a controllable balancing valve means controlling pressure communication between said high pressure and low pressure fluid passages.
 10. A mounting support as set forth in claim 9, said mounting adaptor having a pressure inlet valve disposed in said high range pressure passage upstream of said balancing valve for isolation of said passages from said high pressure.
 11. A mounting support for supporting differential pressure sensing apparatus from the wall structure of a process vessel, said support comprising a support body, connection means and connection flange means formed integrally with said support body at opposite extremities thereof, said connection means being adapted for connection to the wall structure of said process vessel, said connection flange means being adapted for connection to said differential pressure sensing apparatus whereby said support body completely supports said sensing apparatus from said process vessel, said connection flange means defining a connection surface, a high range pressure transmitting passage extending through said support body and terminating at one extremity at said connection means and terminating at the other extremity at said connection surface in off-center relation, low range pressure transmitting passage means extending through said body and terminating at one extremity thereof at said connection surface and terminating at the other extremity thereof at connection aperture means lOcated at the exterior of said support body, means establishing pressure seals between said differential pressure sensing apparatus and about said low and high range pressure transmitting passages.
 12. A mounting support as set forth in claim 11, orienting means extending from said mounting support and cooperating with structure on said differential pressure sensing apparatus to prevent improper assembly of said differential pressure sensing apparatus to said mounting support.
 13. A mounting support as recited in claim 11, said low pressure passage means comprising a plurality of interconnected passages each terminating at connection apertures on different sides of said support body, whereby said mounting support may be oriented in any desired manner and connection may be made between a low pressure supply conduit and a selected one of the interconnected passages and the remaining ones of the interconnected passages may be plugged.
 14. In combination; a vessel having a wall structure, a high pressure aperture formed in the lower portion of said wall structure and a low pressure aperture being defined in the upper portion of said vessel, connection means being defined in said wall structure about said high pressure aperture, a mounting support, first and second connection means being defined on said support, said first connection means being received by said connection means of said vessel and securing said support in assembly with said vessel, differential pressure sensing apparatus being secured to said second connection means and being solely supported by said mounting support, said differential pressure sensing apparatus having a high pressure chamber and a low pressure chamber, first pressure transmittinG passage means being defined in said mounting support and communicating said high pressure aperture with said high pressure chamber, second pressure transmitting passage means being defined in said mounting support and having one extremity thereof disposed in communication with said low pressure chamber and the other extremity thereof terminating at a low pressure connection aperture defined exteriorly of said support, means communicating said low pressure connection aperture of said support, with said low pressure connection aperture of said vessel.
 15. The combination of claim 14, a purge passage being defined in said mounting support and intersecting said first pressure passage means, means communicating said purge passage with a source of purging fluid.
 16. The combination of claim 14, a pressure balancing passage being formed in said mounting support and communicating said first and second pressure passage means, valve means carried by said mounting support and controlling pressure communication between said first and second passage means.
 17. The combination Of claim 16, inlet valve means being carried by said mounting support and controlling communication of pressure from said high pressure aperture of said vessel to said differential pressure sensing apparatus. 